Practice exercise (made-up values, not clinical guidance). A 64 kg adult (BMI below 30) needs 35 kcal/kg/day. The tube feed provides 1 kcal/mL and runs by pump for 16 hours a day. At what rate R do you set the pump, in mL/h? Round to the nearest whole number.
64 kg35 kcal/kg/day1 kcal/mL16 h
R = mL/h
2.Enteral & parenteral nutrition calculationsHard
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 1000 mL of parenteral nutrition with final concentrations of 15% dextrose and 3.5% amino acids, plus 500 mL of 10% lipid emulsion (1.1 kcal/mL). Find the non-protein kilocalorie to nitrogen ratio NPC : N (the number x in x : 1). Round to the nearest whole number.
1000 mLdextrose 15%amino acids 3.5%lipid 500 mL · 1.1 kcal/mL
NPC : N =
3.IV fluids & fluid balanceMedium
Practice exercise (made-up values, not clinical guidance). The record shows a patient's intake and output for one 8-hour shift. The IV infusion ran at the rate shown for the whole shift. Find the total intake I in mL.
juice: 120 mLjelly: 100 mLIV infusion: 60 mL/h × 8 hIV antibiotic: 1 × 50 mL
I = mL
4.IV fluids & fluid balanceHard
Practice exercise (made-up values, not clinical guidance). A 500 mL bag was started at 09:30 and runs by pump at 75 mL/h. How many mL V are left in the bag at 12:30?
500 mL75 mL/h09:30 → 12:30
V = mL
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: R = 140 mL/h
Needs and free water: energy needs are often estimated as kcal/kg/day × weight and protein needs as g/kg/day × weight. A formula is only partly water, so its free water = volume × water fraction; water flushes make up the rest of the daily fluid goal. Ideal body weight (Devine): IBW = 50 kg + 2.3 kg for every inch over 5 feet (60 in) for men, and 45.5 kg + 2.3 kg per inch over 60 in for women; 1 in = 2.54 cm. The formula is meant for adults at least 152.4 cm (5 ft) tall. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Energy needed
E = 35·64 = 2240 kcal/day
Daily volume
V = 2240/1 = 2240 mL/day
Pump rate
R = 2240/16 = 140 mL/h
Answer
R = 140 mL/h
2.Enteral & parenteral nutrition calculations
Answer: NPC : N = 189
Parenteral nutrition: dextrose provides 3.4 kcal/g, amino acids 4 kcal/g and lipid emulsion the kcal/mL stated (2 kcal/mL for 20%, 1.1 kcal/mL for 10%). Grams = % × mL/100. Non-protein kcal (NPC) = dextrose + lipid kcal; nitrogen = protein/6.25. The glucose infusion rate (GIR) in mg/kg/min = dextrose mg/(kg × minutes). The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Grams of dextrose and amino acids
dextrose: 15·1000/100 = 150 g
amino acids: 3.5·1000/100 = 35 g
Kilocalories per component
dextrose: 150·3.4 = 510 kcal
amino acids: 35·4 = 140 kcal
lipid: 500·1.1 = 550 kcal
Non-protein kcal and nitrogen
NPC = 510 + 550 = 1060 kcal
N = 35/6.25 = 5.6 g
Ratio
NPC : N = 1060/5.6 = 189.3 ≈ 189 : 1
Answer
NPC : N = 189
Ratios of about 150 : 1 are typical for stable patients; lower ratios give relatively more protein.
3.IV fluids & fluid balance
Answer: I = 750 mL
Intake and output: intake counts everything that goes in (oral fluids, IV infusions, IV medications and flushes, tube feeds); ice chips count as half their volume. Output counts urine, drains, vomit and other losses. Balance = total intake − total output; a negative balance is a net loss. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Add the intake
oral: 120 + 100 = 220 mL
IV infusion: 60·8 = 480 mL
IV antibiotic: 1·50 = 50 mL
I = 750 mL
Answer
I = 750 mL
4.IV fluids & fluid balance
Answer: V = 275 mL
Infusion time: time (h) = volume to infuse (mL)/rate (mL/h); use the volume still left in the bag, not the bag size. Volume infused = rate × time. Convert decimal hours to hours and minutes with the fraction × 60 (0.5 h = 30 min, not 50 min). The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.